Perfect cast and a good story

It's funny, it's tense, it features two great performances from two actors and the director expertly creates a web of odd tension where you actually don't know what is happening for the majority of the run time.

By the time the dramatic fireworks start popping off, each one feels earned.

While it is a pity that the story wasn't told with more visual finesse, this is trivial compared to our real-world problems. It takes a good movie to put that into perspective.